Editor’s note: We turned to two public health researchers on gun violence to help us understand the mass shooting at Pulse nightclub in Florida. Sandro Galea is the dean of Boston University’s School of Public Health. Ziming Xuan is an assistant professor at the school who recently led a study of state gun laws and youth gun-carrying in the United States. We originally spoke to the researchers in the wake of the mass shooting at Umpqua Community College in Oregon in October 2015.

Q: How common are mass shootings in the U.S.? Do you consider gun violence a public health issue?

Sandro Galea: Mass shootings have been occurring with regularity in the U.S. for years now, but they are far from the only way people are affected by gun violence in this country. There were 64 school shootings in America in 2015. More than 32,000 people die from firearms every year, as many as die from car accidents. This is clearly a public health issue, and one with a solution – the control of widespread gun availability. This approach has been shown to work in countries like Australia.

Ziming Xuan: How common are mass shootings? One indication is that after the Umpqua shooting last October, President Obama spoke about the “routine” nature of mass shootings in our country.

We’ve regularly heard from the president on the issue. After the Kansas mass shooting in February 2016, Obama also urged the country not to become numb to gun violence. And just this weekend, he said: “to actively do nothing is a decision as well.”

While mass shootings galvanize the nation’s attention, a sad truth is that mass shootings represent a very small proportion of total firearm homicides in U.S. In 2012, fewer than one percent of firearm homicide victims were killed in mass shootings, defined by the FBI as a shooting with four or more victims. Gun violence is often among the leading causes of death (homicides and suicides) and nonfatal injuries among youth, and affects families and communities across the U.S.

Gun violence has created a major and unique public health problem for the U.S., compared to other developed countries. In order to protect youth, the governments and adults in other developed countries such as France have made it difficult for youth to access handguns. However, a recent study showed that about a quarter of U.S. adolescents reported they had easy access to a gun in their home. Meanwhile, the majority of young respondents told researchers they wished to live in a society where it is impossible for teens to obtain guns.

Q: What else should people know to understand gun violence in the U.S.?

Sandro Galea: Firearm deaths are driven principally by availability of firearms. While frequently after these events we link them to mental illness, the evidence is very clear that this is a negligible part of the problem. People with mental illness are much more likely to be victims than perpetrators of firearm violence.

Ziming Xuan: Considering the magnitude of the gun violence problem in the U.S., gun-related research is limited in part because there is very limited funding from the federal government to advance our understanding about the nature and mechanism of gun violence or to evaluate and identify effective prevention strategies.

Parents definitely need to teach their children to be responsible with risky and lethal products such as alcohol, guns, cars and so on. However, parents sometimes do not fully understand child and youth development, impulsiveness or curiosity.

A recent study shows that what parents report about their children’s access to guns often contradicts children’s reports. The kids reveal that they know the location of guns in the house and have handled the gun, while parents reported they did not. For injury prevention, it is far more effective and long-lasting to change the environment by changing modifiable policies and norms than to try to change the way children behave.